From 5c4882bfc0182195500c24277d79a9993f58ee28 Mon Sep 17 00:00:00 2001
From: P. J. McDermott <pjm@nac.net>
Date: Tue, 05 Mar 2013 14:33:18 -0500
Subject: src/main.c: It's summer somewhere...

---
(limited to 'src')

diff --git a/src/main.c b/src/main.c
index a8700cd..0873005 100644
--- a/src/main.c
+++ b/src/main.c
@@ -11,28 +11,42 @@
 	do {                                                                   \
 		vp->x = x + map->tilewidth / 2 - vp->w / 2;                    \
 		vp->y = y + map->tileheight / 2 - vp->h / 2;                   \
-		if (i % i_max < i_max / 4) {                                   \
+		/*                                                             \
+		 * See the following resources when computing realistic        \
+		 * daylight cycles:                                            \
+		 *   * <https://en.wikipedia.org/wiki/Sunrise_equation>        \
+		 *   * <http://www.esrl.noaa.gov/gmd/grad/solcalc/sunrise.html>\
+		 */                                                            \
+		if (i % i_max < i_max / 6 * 2) {                               \
+			/* 00:00 - 04:00 */                                    \
+			t_max = i_max / 6 * 2;                                 \
 			pal_start = map->palettes[MAP_PALETTE_MORN]            \
 				.palette->palette;                             \
 			pal_end = map->palettes[MAP_PALETTE_DAY]               \
 				.palette->palette;                             \
-		} else if (i % i_max < i_max / 4 * 2) {                        \
+		} else if (i % i_max < i_max / 6 * 4) {                        \
+			/* 04:00 - 12:00 */                                    \
+			t_max = i_max / 6 * 2;                                 \
 			pal_start = map->palettes[MAP_PALETTE_DAY]             \
 				.palette->palette;                             \
 			pal_end = map->palettes[MAP_PALETTE_EVE]               \
 				.palette->palette;                             \
-		} else if (i % i_max < i_max / 4 * 3) {                        \
+		} else if (i % i_max < i_max / 6 * 5) {                        \
+			/* 12:00 - 20:00 */                                    \
+			t_max = i_max / 6 * 1;                                 \
 			pal_start = map->palettes[MAP_PALETTE_EVE]             \
 				.palette->palette;                             \
 			pal_end = map->palettes[MAP_PALETTE_NIGHT]             \
 				.palette->palette;                             \
 		} else {                                                       \
+			/* 04:00 - 12:00 */                                    \
+			t_max = i_max / 6 * 1;                                 \
 			pal_start = map->palettes[MAP_PALETTE_NIGHT]           \
 				.palette->palette;                             \
 			pal_end = map->palettes[MAP_PALETTE_MORN]              \
 				.palette->palette;                             \
 		}                                                              \
-		if (!cycle_palettes_cosine(i, i_max / 4,                       \
+		if (!cycle_palettes_cosine(i, t_max,                           \
 					pal_start, pal_end, pal)) {            \
 			warn("Failed to cycle palettes");                      \
 		}                                                              \
@@ -86,7 +100,7 @@ main(void)
 	/* Demo */
 	{
 		Uint32 start, end;
-		int i, i_max;
+		int i, i_max, t_max;
 		int x, y;
 		SDL_Palette *pal_start, *pal_end;
 
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